1. Technical Field
The present disclosure relates to an electronic device capable of connecting with an external device via an USB (Universal Serial Bus) interface.
2. Related Art
USB devices are known as electronic devices having a plurality of functions. The USB devices having plurality of functions store a plurality of USB descriptors (hereinafter, “descriptor”) as information indicating the respective functions.
Various approaches to establishing communication between such a USB device and a host device have been proposed. For example, JP2005-78304A describes an USB function device (USB device) as discussed below. In general, upon the USB function device being connected to a host device, the host device requests a descriptor from the USB function device. In response to the request, the USB function device sends a descriptor indicating one function pre-selected by a user out of a plurality of functions to the host device. When the host device does not support the function indicated by the sent descriptor, after a certain time period, the USB function device selects another descriptor. Here, the second descriptor indicates a function different from the function indicated by the previously sent first descriptor. Then, the USB function device starts an USB bus reset for initializing the communication between the USB function device and the host device. When reconnected to the host device after the USB bus reset, the USB function device sends the selected second descriptor to the host device in response to the request from the host device for a descriptor. T Accordingly, the USB function device described in JP2005-78304A has an improvement in the capability of establishing connection with the host device.